Born on 15 April 1927 in Englewood, New Jersey, Robert L. Mills was a physicist who specialized in quantum field theory, the theory of alloys, and many-body theory. After serving in the US Merchant Marine from 1944 to 1947, Mills earned a bachelor’s degree from Columbia University, a master’s from Cambridge University, and a PhD from Columbia. In 1953 as a research associate at Brookhaven National Laboratory, Mills coauthored with Chen Ning Yang a landmark scientific paper in which they proposed the Yang–Mills theory, a generalization of Maxwell’s equations that seeks to describe the behavior of elementary particles and explain the electromagnetic and nuclear forces. The theory is one of the bases of the standard model of particle physics. Two years later Mills became a member of the Institute for Advanced Study in Princeton, New Jersey. In 1956 he joined the physics department at Ohio State University, where he taught for the next 39 years. After retiring in 1995, he taught for a year as a Fulbright scholar at St Patrick’s College in Ireland and wrote two books, Propagators for Many-Particle Systems (1969) and Space, Time and Quanta (1994). Mills died in 1999 at age 72. (Photo credit: State University of New York at Stony Brook, courtesy AIP Emilio Segrè Visual Archives)
